A colorimetric platform based on Cu2MoS4 nanozyme with peroxidase-like activity for the sensitive sensing of proline

Abstract

Herein, a two-dimensional ternary chalcogenide nanozyme (Cu₂MoS₄) was synthesized via a hydrothermal method. Generally, Cu₂MoS₄ exhibits peroxidase (POD)-like activity under acidic conditions. Interestingly, in this work, proline (Pro) improved the POD-like activity of Cu₂MoS₄, attributing to increasing its substrate affinity and thereby generating more ˙OH radicals. In the presence of H₂O₂, Cu₂MoS₄-Pro effectively catalyzed the conversion of colorless 2,2′-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) to green oxidized-ABTS (oxABTS). Accordingly, a sensitive method for the colorimetric detection of Pro using Cu₂MoS₄ was established, with Pro solutions in a linear concentration range of 3–780 μg L⁻¹. The developed colorimetric probe demonstrated excellent performance in real tobacco sample analysis, showing satisfactory recovery rates ranging from 87.50% to 113.94% while maintaining a low detection limit of 1.37 μg L⁻¹ (calculated as 3.3σ/k). Thus, this nanozymatic colorimetry-based method provides a visual strategy for the detection of Pro in tobacco.